Excitations of 21+ and 31- states from (p,p') and electromagnetic measurements

A reanalysis of (p,p') data taken on 21+ and 31- states of 37 even-even A≥40 nuclei at energies of E<50 MeV has been performed with a consistent procedure involving coupled-channels calculations and Becchetti-Greenlees optical model parameters. The matrix elements extracted from this analysis have been compared to matrix elements deduced from electromagnetic measurements of the same excitations. It is concluded that the differences between (p,p') and electromagnetic results which are often observed do not result from variations in the method of analysis of the (p,p') data. Instead, the differences are caused by experimental errors and nuclear structure effects. The nuclear structure effects are examined by extracting the ratios Mn/Mp of the neutron and proton multipole matrix elements for both the 21+ and 31- states from the proton and electromagnetic data